432 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



safely, is free from such a tendencj^, and burns with excellent 

 effect, quietly, and comparatively slowly, and even when 

 strewn upon the damp ground : one part, by weight, of shel- 

 lac, and four of thoroughly dried nitrate of strontia are well 

 mixed, in an unpulverized condition, in a tin dish, and heated 

 to the melting-point of the shellac, and the semi-fused mass 

 is pulverized after cooling. 5 C, 1874, XIII., 103. 



MAINTENANCE OF A UNIFORM TEMPERATURE. 



General Morin has proposed a method, both simple and 

 inexpensive, of maintaining a temperature as constant as 

 possible in a given locality through all the seasons of the 

 year. The principle he announces is simply that of regular- 

 ly renewing the air of any given place by causing cool air 

 of a constant temperature to flow into it by the aid of a 

 moderate aspiration. In order to obtain this cool air, he 

 states that at a depth of about seventy feet in the earth the 

 temperature is constant, and that it is to this fact that is due 

 the uniform temperature of several French public halls al- 

 luded to by him, which are supplied with air drawn through 

 subterranean galleries. He gives, also, an elaborate calcula- 

 tion of the quantity of air, at a given temperature, necessary 

 to be introduced into any apartment in order to keep it in a 

 uniform condition (somewhat cooler than the average sum- 

 mer temperature), and shows that to maintain such a tem- 

 perature it is not necessary to have recourse to the employ- 

 ment of deep caves, expensive to construct and to keep free 

 from watery infiltrations ; but that, on the contrary, by a 

 proper arrangement of rooms one can establish the reservoir 

 of cold either at the level of the soil or at a moderate depth 

 beneath it, giving it plenty of fresh air and sunlight, and in 

 which a temperature a little lower than that of spring-time 

 can be maintained without inconvenience. 6 .Z?, November^ 

 1873, 743. 



WOODEN SOLES FOR SHOES. 



Wooden shoe-soles are manufactured by Bohme, of Schan- 

 dau, by means, of a machine specially devised for the pur- 

 pose. These internally have the shape of the foot, and when 

 attached to leather uppers form shoes not only as elegant in 

 appearance, but as comfortable, it is said, as those with 



